Carburetor with fluid amplifying elements

ABSTRACT

A carburetor employing three pure fluid amplifiers. Fuel from a supply source is applied to the power inputs of a first and a second amplifier, with a power outlet of the second amplifier being connected to the power inlet of the third amplifier. One power outlet of each amplifier terminates at an opening in a cylinder wall upstream of a throttle valve for supplying fuel to the cylinder. One control input of each amplifier terminates at an opening in the cylinder wall for sensing the pressure therein and controlling the amplifiers to supply fuel at a rate dependent upon the pressure sensed. The arrangement is such that one, two or all three amplifiers may supply fuel to the cylinder.

United States Patent [54] CARBURETOR WITH FLUID AMPLIFYING PrimaryExaminer-Tim R. Miles At!0rneyGriffin, Branigan & Kindness ABSTRACT: Acarburetor employing three pure fluid am- ELEMENTS 4 Claims 4 DrawingFigs plifiers. Fuel from a supply source is applied to the power inputsof a first and a second amplifier, with a power outlet of U.S. CL thesecond am lifier being connected to the ower inlet of the 261/41,261/69, 137/815 123/119 third amplifier. One power outlet of eachamplifier terminates [51] Int. Cl. F02m 7/04 at an Opening in a cylindern upstream f throttle valve f [50] Field ofSearch 261/361, supplying f lto the cylinder o comm] input f each 1 137/81-5; 123/119 plifierterminates at an opening in the cylinder wall for sensing the pressuretherein and controlling the amplifiers to supply [56] References cuedfuel at a rate dependent upon the pressure sensed. The ar- UNITED STATESPATENTS rangement is such that one, two or all three amplifiers may3,191,611 6/1965 Bauer 137/8 1.5 supply fuel to the cylinder.

$2 2 4 I?! i 492 :9? j e 1%2 cf 6 2 7 i Gr CAREURETOIR WITH FLUIDAMPLIFYING ELEMENTS PRIOR ART FIG. ll illustrates a typical prior artdevice employing a fluid amplifier. As shown in FIG. l, the fuel in thefuel tank 3 is forced out by the fuel pump 2 and is supplied to thesupply port of the fluid amplifier 1 having power output outlets P P andP The controlling signal (fluid) circuit, which is connected to thecontrol circuit terminals C and C of the fluid amplifier l, is opened atthe upstream and downstream of the throttle valve 5 of the cylinder 4,respectively, and a fluid amplifying element isused to control thequantity of fuel supplied to the cylinder 4 from the power outputoutlets P and P in accordance with engine operation conditions. Thecarburetor of this type is well known. Since only one fluid element withmultiple power output outlets is used to-control the fuel supply fromthe idling state to the state of full power output, a highly accurateelement is needed. It is difficult for one fluid element to control thefuel supply in accordance with the need of the engine, i.e., a rich fuelmixture is needed during the idling, a (lean) economical fuel mixtureduring the state of partial power output, and a rich fuel mixture duringthe state of full power output. Various auxiliary equipment is needed,causing difficulty in mass production. Furthermore, this device requiresa controlling vacuum outlet downstream of the throttle valve where it isaffected by changes in manifold vacuum. This creates the possibility ofa large quantity of fuel being injected during periods of acceleration.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a carburetor which has none of the disadvantages enumeratedabove.

An object of the present invention is to provide a carburetor havingplural fluid amplifying elements for controlling fuel flow.

An object of the present invention is to provide plural fluid amplifiersfor controlling fuel flow to a cylinder, said ampliflers beingselectively and successively operated to supply said fuel in response tothe pressure within said cylinder.

In a first embodiment of the invention, a combination of fluid elementsis employed. The outputs of each element are additively supplied to theengine and thus the quantity of fuel can be controlled in a wide range.There is a time lag in the start of operation of each fluid-amplifyingelement, and the fuel flow from each fluid-amplifying element issupplied additively to the engine. The nozzle for supplying fuel as wellas the vacuum outlet for controlling fuel are all located at theupstream of the throttle valve to decrease'the effect caused by themanifold vacuum.

A second embodiment also employs multiple fluid-amplifying elements.Similarly, there is a time lag in the start of operation of eachfluid-amplifying element, and the fuel flow from each fluid-amplifyingelement is also supplied additively to the engine. To one of theelements is installed a circuit switch operated by vacuum to control thestarting time of operation of the element. This circuit switch isconnected to the vacuum portion of the engine to supply an overly richfuel mixture during the period of low boost.

BRIEF EXPLANATION OF TI IE FIGURES FIG. I shows the pipe arrangement ofa conventional carburetor with fluid-amplifying elements;

FIG. 2 shows the pipe arrangement of carburetors invented;

FIG. 3 shows the fuel characteristics of the carburetors shown in FIG.2; and

FIG. 4(A), (1B) and (C) are the longitudinal sections of various circuitswitches used in the invented carburetors.

DETAILED EXILANATION OF THE INVENTION The carburetors invented are nowexplained by the use of FIGS. When the engine is started, the fuel pump2 shown in FIG. 2 will start to operate; the fuel is drawn from the fueltank 3 and forced into the supply ports of the fluid elements 10 and 20.The fluid element 10 always supplies a small quantity of idling fuelflow to the cylinder 4 from the power output outlet P through the nozzle7. The excess fuel which was sent to the supply port of the fluidelement from the fuel pump 2 is returned to the tank 3 from the poweroutput outlet P The fuel sent to the fluid element 20 is forced into thesupply port of the fluid element 30 through the power output outlet Pand is returned to the fuel tank 3 from the power output outlet P Thestarting level of the operation of the fluid element 20 is so presetthat it will not start operation even though the cylinder vacuum duringthe idling is present at the control circuit terminal C of the fluidelement 20.

During the partial power output of the engine, the throttle valve willopen and the quantity of air passing through the cylinder 4 isincreased. Consequently, the cylinder vacuum will increase in accordancewith the quantity of air sucked in. From the vacuum outlet 6 which opensat the cylinder sidewall, the cylinder vacuum will be transferredthrough the fluid circuit used for transferring the control signal, andwill be impressed simultaneously upon one side of the control circuitterminals C11, C and C of each fluid element. Since the other side ofthe control circuit terminals C and C of the fluid elements 10 and 20are connected to atmospheric air, the aforementioned cylinder vacuum asa control signal will be impressed on the control circuit terminals Cand C as mentioned above, and the cylinder vacuum is graduallyincreased. Subsequently, the quantity of fuel flowing out of the poweroutput outlet P of the fluid element 10 is also increased in accordancewith the degree of the cylinder vacuum. When the quantity of the fuelflow reaches a certain degree, the quantity of the fuel flowing out of Pwill no longer increase even though the cylinder vacuum is increasedfurther, i.e., a saturated state is reached. In this way, when thecylinder vacuum becomes slightly smaller than the cylinder vacuum atwhich the fluid element 10 becomes saturated, the fluid element 20 willstart to operate and the fuel from the power output outlet P begins tobe fed into the cylinder 4 via the nozzle 8. When the cylinder vacuum isincreased further, the negative pressure on the control circuit terminalC will also increase. Therefore, the output from the fluid element 20will be shifted gradually from the power output outlet Pto P In thisstate, the fuel supplied to the engine is equal to the sum of the fuelfrom the power output outlets P and P During this state of partial poweroutput of the engine, the circuit switch 11 connected to the controlcircuit terminal C of the fluid element 11 is closed, and thus the fluidelement 30 will not perform its control activity. Consequently, all thefuel supplied to the fluid element 30 is returned to the fuel tank 3from the power output outlet P As will be mentioned later, when theengine is in the state of full power output, the circuit switch 11interlocked with the throttle valve 5 will be opened, and the controlcircuit terminal C of the fluid element 30 is connected to atmosphericair to start the operation of the fluid element 30. The fuel drawn fromthe output opening P will be added to the fuel from the aforementionedpower output outlets P and P in accordance with the increase in thecylinder vacuum, and is supplied to the engine. 9 is the nozzlefor-supplying fuel to the cylinder from the power output outlet P FIG. 3shows the relationship between the cylinder vacuum of the carburetorwith fluid-amplifying elements, as shown in FIG. 2, and the quantity offuel flow. In this FIG., the curve 1 represents the quantity of fuelsupplied to the engine from the power output outlet P of the fluidelement 10; the curve 2 represents the fuel shown in the curve 1 plusthe additional fuel supplied from the power output outlet P of the fluidelement 20. The curve 3, in addition to the fuel given by the curves 1and 2, also includes the fuel from the power output outlet P of thefluid element 30. The area A enclosed by curve 1, the vertical axis andthe horizontal axis indicates the amount of fuel to be supplied by thefluid element 10. The area B enclosed by the curves 1 and 2 representsthe amount of fuel to be supplied by the fluid element 20, and the areaC between the curves 2 and 3 represents the amount of fuel to besupplied by the fluid element 30.

Various circuit switches 11 connected to the control circuit terminal 32of the fluid element 30 shown in FIG. 2 are shown in FIG. 4(A), (B) and(C). FIG. 4(A) is a mechanically operated circuit switch. Its main body12 contains the opening 13 connected to the control circuit terminal C32of the fluid element 30 and the opening 14 connected to atmospheric air.The piston 15 which can connect or disconnect the two openings 13 and 14is also present in the main body. The spring 16 is used to keep thepiston to the right. The piston is interlocked with the throttle valveand is pressed by the cam 18 which rotates around the axle 17. Duringthe full power output of the engine, the cam 18 will push the piston tothe left as shown in FIG. 4(A), and the hole 15 which passes through atabout the center of the piston 15 will move to a proper position toconnect the openings 13 and 14. Consequently, the fluid element 30 willstart to operate as mentioned earlier and supply the fuel for full poweroutput.

The circuit switch shown in FIG. 4(B) also contains within its main body12 the piston 15 and the spring which keeps the piston to the right atall times. It also contains the vacuum connection opening 19 connectedto the chamber enclosed by the piston 15 and the main body 12 andlocated at the left side of the piston. The vacuum connection opening 19is connected to the engine manifold or the vacuum portion of the enginelocated at the downstream of the throttle valve. When the degree ofvacuum is about that of the full power output of the engine (about 60mmI-lg) the spring 16 can work against the vacuum to push the piston 15toward the right, and the openings 13 and 14 are connected through thehole 15. The fluid element will then start to operate. During thepartial power output of the engine, the negative pressure in the vacuumportion of the engine will increase, and the negative pressure createdin the chamber on the left side of the piston will work against thespring 16 to suck the piston toward the left. The openings 13 and 14 arenow closed.

The circuit switch shown in FIG. 4(C) is operated electromagnetically.The piston 15 in the main body 12 consists of the plunger 22 and thecoils 21 and is kept to the left side at all times by the action of thespring 16. The coils 21 are connected in series to a switch and abattery. The switch will be closed when the accelerator pedal of anautomobile is depressed deeply. Therefore, during the full power outputof the engine, the aforementioned switch interlocked with theaccelerator pedal is closed and the excitation current will flow throughthe coils. The plunger 22 will be sucked in and thus the piston 15 willwork against the spring 16 to move toward the right. The openings 13 and14 are now connected through the hole 15 and the fluid element 30 willstart to operate to supply additional fuel for the full operation of theengine. During the partial power output, the switch connected to theaccelerator pedal will open and the excitation current of the coils 21will be shut off. Therefore, the piston 15 will be pushed toward theleft by the action of the spring 16 to shut off the connection betweenthe openings 13 and 14. Subsequently, the fluid element will stopperforming its controlling action and the fuel for the full operation ofthe engine cannot be supplied, and only the fuel from the fluid elements10 and will be supplied to the engine.

In the carburetor shown in FIG. 2, the controlling signals applied onthe control circuit terminals C C and C of each fluid element areobtained from the same vacuum outlet 6. However, the signals can beobtained from their respective vacuum outlets which have their exits inthe cylinder 4. Since one side of the control circuit terminals of eachfluid element is exposed to atmospheric air, the control signal obtainedis the difference between the atmospheric pressure and the negativepressure in the cylinder. Therefore, the size of signal will change withvarying atmospheric pressures. In order to avoid this variation, one caninstall in the cylinder 4 a stage having a different diameter from thatof the cylinder, or multiple cylinders with different diameters, and thepressure differences between the two places having different pressuresin the cylinder is used as a control signal for the fluid elements.

In order to carry out the microadjustment of the starting time of theoperation (fuel supply) of each fluid element (namely, level of startingsignal) and the quantity of fuel flow, an adjusting screw and jet whichcan act as an adjustable throttle are installed either on the controlcircuits of each fluid element or on the passage (the fluid circuit)connected to the power output outlets, or both.

For the determination of the starting time of the operation of the fluidelements 20 and 30, the circuit switch can be installed at the fuelintake opening connected to the supply port of the fluid element, or onthe control circuits, or on various passages of the power output outlet.

The fluid elements 10, 20 and 30, can be connected in series. This pipearrangement will result in the fuel from the power output outlet P ofthe fluid element 10, as shown in FIG. 2, becoming the fuel to be fedinto the supply port of the fluid element 20. The characteristiccapacity of this pipe arrangement is about the same as that of thearrangement shown in FIG. 2.

According to this invention, the multiple fluid amplifying elements willstart to operate gradually and successively as the power output of theengine increases in accordance with the performance of the engine. Atthe beginning, the engine is operated solely by the output fuel from onefluid element. During the full power output of the engine, total outputsfrom all fluid elements are supplied to the engine. Because of thecharacteristics mentioned above, it is not necessary to especiallyimprove the processing accuracy of each fluid element in order for theentire system to be able to provide the fuel supply in accordance withfuel characteristics requested by the engine. Since no controllingvacuum outlet is present at the downstream of the throttle valve, thesystem will be affected very little by the manifold vacuum, and thepossibility of a large quantity of fuel flow during the decelerationperiod is eliminated.

In the case in which the circuit switch operated by negative pressure ispresent, the system can automatically supply an over-rich gas mixture inaccordance with the requirements of the engine during the low boost,full power output operation. At the start of the engine, the crankingnegative pressure is low, but the system described above can stillimprove the starting property of the engine by opening the circuitswitch for the addition of small quantities of fuel.

We claim:

1. A carburetor for controlling the flow of fuel to a cylinder bore,said carburetor comprising:

a throttle valve in said bore;

a plurality of fluid-amplifying means each having a power input, firstand second control inputs, and first and second power outputs to whichfuel supplied to said power input may be selectively directed inresponse to signals at said control inputs;

each of said fluid-amplifying means having an internal configurationsuch that a control signal of a different magnitude is required at saidfirst control inputs in order to direct fuel from said first to saidsecond power output;

means for conveying fuel from one of said power outputs of eachamplifier to said cylinder bore;

means for conveying to said first control inputs the pressure in saidbore;

switch means for selectively blocking said second control input ofone ofsaid fluid-amplifying means, or connecting it to the atmosphere;

means interlocking said switch with said throttle valve whereby saidswitch means connects said second control input to atmosphere when saidthrottle valve is opened; and

means connecting said second control input of each of the otherfluid-amplifying means to the atmosphere.

2. A carburetor as claimed in claim 1 wherein said means for conveyingfluid pressure comprises fluid passage means communicating with saidbore upstream of said throttle valve.

3. A carburetor for controlling the flow of fuel to a cylinder bore,said carburetor comprising:

each amplifier to said cylinder bore means for conveying to said firstcontrol inputs the pressure in said bore;

pressure-responsive switch means for selectively blocking said secondcontrol input of one of said fluid-amplifying means, or connecting it tothe atmosphere;

a fluid passage connected to said switch means and terminating atanopening in said bore downstream from said throttle valve foroperating'said switch in response to a negative pressure ofpredetermined value; and

means connecting said second control input of each of the otherfluid-amplifying means to the atmosphere.

4. A carburetor as claimed in claim 3 wherein said means for conveyingfluid pressure comprises fluid passage means communicating with saidbore upstream of said throttle valve.

1. A carburetor for controlling the flow of fuel to a cylinder bore,said carburetor comprising: a throttle valve in said bore; a pluralityof fluid-amplifying means each having a power input, first and secondcontrol inputs, and first and second power outputs to which fuelsupplied to said power input may be selectively directed in response tosignals at said control inputs; each of said fluid-amplifying meanshaving an internal configuration such that a control signal of adifferent magnitude is required at said first control inputs in order todirect fuel from said first to said second power output; means forconveying fuel from one of said power outputs of each amplifier to saidcylinder bore; means for conveying to said first control inputs thepressure in said bore; switch means for selectively blocking said secondcontrol input of one of said fluid-amplifying means, or connecting it tothe atmosphere; means interlocking said switch with said throttle valvewhereby said switch means connects said second control input toatmosphere when said throttle valve is opened; and means connecting saidsecond control input of each of the other fluid-amplifying means to theatmosphere.
 2. A carburetor as claimed in claim 1 wherein said means forconveying fluid pressure comprises fluid passage means communicatingwith said bore upstream of said throttle valve.
 3. A carburetor forcontrolling the flow of fuel to a cylinder bore, said carburetorcomprising: a throttle valve; a plurality of fluid-amplifying means eachhaving a power input, first and second control inputs, and first andsecond power outputs to which fuel supplied to said power input may beselectively directed in response to signals at said control inputs; eachof said fluid-amplifying means having an internal configuration suchthat a control signal of a different magnitude is required at said firstcontrol inputs in order to direct fuel from said first to said secondpower output; means for conveying fuel from one of said power outputs ofeach amplifier to said cylinder bore; means for conveying to said firstcontrol inputs the pressure in said bore; pressure-responsive switchmeans for selectively blocking said second control input of one of saidfluid-amplifying means, or connecting it to the atmosphere; a fluidpassage connected to said switch means and terminating at an opening insaid bore downstream from said throttle valve for operating said switchin response to a negative pressure of predetermined value; and meansconnecting said second control input of each of the otherfluid-amplifying means to the atmosphere.
 4. A carburetor as claimed inclaim 3 wherein said means for conveying fluid pressure comprises fluidpassage means communicating with said bore upstream of said throttlevalve.